Video decoding method and apparatus and video encoding method and apparatus

Abstract

In video encoding and decoding processes, in order to add a motion vector when the motion vector is insufficient in a motion vector prediction value candidate list of a current block, provided are method and apparatus for determining a base motion vector in a motion vector candidate list, determining the motion vector candidate list including an additional motion vector candidate determined based on the determined base motion vector and predetermined offset information, and determining a motion vector of the current block by using an additional motion vector candidate determined in the motion vector candidate list.

The invention claimed is: 
     
       1. A video decoding method comprising:
 determining whether to add a motion vector to a motion vector candidate list of a current block; 
 when it is determined to add the motion vector, determining a base motion vector in the motion vector candidate list; 
 determining the motion vector candidate list comprising an additional motion vector candidate determined based on the base motion vector and predetermined offset information; and 
 determining a motion vector of the current block by using the additional motion vector candidate determined in the motion vector candidate list, 
 wherein, when a prediction mode of the current block is one of a skip affine mode, a merge affine mode, and an inter affine mode, 
 wherein the motion vector, the base motion vector, and the additional motion vector candidate of the motion vector candidate list are affine-transformed motion vectors, and 
 wherein the affine-transformed motion vectors are 4 affine parameters. 
 
     
     
       2. The video decoding method of  claim 1 , wherein the base motion vector is selected from among motion vectors of adjacent blocks neighboring the current block. 
     
     
       3. The video decoding method of  claim 1 , wherein a plurality of motion vectors are determined as the base motion vector. 
     
     
       4. The video decoding method of  claim 1 , wherein the predetermined offset information comprises at least one offset value. 
     
     
       5. The video decoding method of  claim 1 , wherein the base motion vector comprises a motion vector that is not selected in a process of configuring the motion vector candidate list. 
     
     
       6. A video decoding method comprising:
 determining whether to add a motion vector to a motion vector candidate list of a current block; 
 when it is determined to add the motion vector, determining a base motion vector in the motion vector candidate list; 
 determining the motion vector candidate list comprising an additional motion vector candidate determined based on the base motion vector and predetermined offset information; and 
 determining a motion vector of the current block by using the additional motion vector candidate determined in the motion vector candidate list, 
 wherein, when a prediction mode of the current block is one of a skip affine mode, a merge affine mode, and an inter affine mode, 
 wherein the motion vector, the base motion vector, and the additional motion vector candidate of the motion vector candidate list are affine-transformed motion vectors, and 
 wherein the affine-transformed motion vectors are 6 affine parameters. 
 
     
     
       7. The video decoding method of  claim 1 , wherein the predetermined offset information comprises a value obtained from signaled information. 
     
     
       8. A video encoding method comprising:
 determining whether to add a motion vector to a motion vector candidate list of a current block; 
 when it is determined to add the motion vector, determining a base motion vector in the motion vector candidate list; 
 determining the motion vector candidate list comprising an additional motion vector candidate determined based on the base motion vector and predetermined offset information; and 
 determining a motion vector difference value and a reference index of the current block by using the additional motion vector candidate determined in the motion vector candidate list; 
 wherein, when a prediction mode of the current block is one of a skip affine mode, a merge affine mode, and an inter affine mode, 
 wherein the motion vector, the base motion vector, and the additional motion vector candidate of the motion vector candidate list are affine-transformed motion vectors, and 
 wherein the affine-transformed motion vectors are 4 affine parameters. 
 
     
     
       9. A video decoding apparatus comprising:
 a memory; and 
 at least one processor connected with the memory, 
 wherein the at least one processor is configured to
 determine whether to add a motion vector to a motion vector candidate list of a current block, 
 when it is determined to add the motion vector, determine a base motion vector in the motion vector candidate list, 
 determine the motion vector candidate list comprising an additional motion vector candidate determined based on the base motion vector and predetermined offset information, and 
 determine a motion vector of the current block by using the additional motion vector candidate determined in the motion vector candidate list, 
 wherein, when a prediction mode of the current block is one of a skip affine mode, a merge affine mode, and an inter affine mode, 
 wherein the motion vector, the base motion vector, and the additional motion vector candidate of the motion vector candidate list are affine-transformed motion vectors, and 
 wherein the affine-transformed motion vectors are 4 affine parameters.